This invention relates to a ventilating arrangement for an engine compartment of a liquid-cooled internal combustion engine wherein the coolant of the internal combustion engine is recooled by means of ambient air in a radiator arranged in an air-conducting housing separated from the engine compartment; and wherein a partial amount of the cooling air conveyed by the cooling air fan is passed through the engine compartment for ventilation and cooling purposes.
In conventional ventilating arrangements, "cold" cooling air is branched off between the cooling air fan and the radiator and fed to the engine compartment. This branched-off quantity of cooling air is for the recooling of the engine coolant. As a consequence, disadvantages are encountered in two respects in the conventional ventilating arrangements:
(A) The cooling air fan must be designed for an air throughput which is larger by the amount of the branched-off cooling air (about 5-10% of the air throughput) than would be required for the amount of heat to be removed by the radiator. This means a higher power requirement for the cooling air fan and a larger structural size of the cooling unit.
(B) Although the ventilation of the engine compartment is effected with "cold" cooling air, the efficiency is unsatisfactory, because the amount of cooling air branched off for the ventilation of the engine compartment must be dimensioned to be relatively minor, considering the cooling of the internal combustion engine, and thus a uniform ventilation throughout the engine compartment is not attained. Thereby, so-called hot spots are formed in the engine compartment on insufficiently ventilated locations, with an increased air temperature.
It is, therefore, an object of this invention to provide a ventilating arrangement which does not exhibit the above-described disadvantages. This object is attained by providing that the ventilation and cooling are effected by means of radiator exhaust air; that a conventional, so-called ring radiator is utilized as the radiator; that a subdivision of the air-conducting housing into two waste air chambers is achieved by the shape of the sidewalls of the air-conducting housing when the ring radiator has been installed, different peripheral zones of the ring radiator being associated with these waste air chambers; and that one of the waste air chambers is in communication with the engine compartment via at least one opening, whereas the other waste air chamber is in direct communication with the surroundings via an air outlet.
These measures make it possible to limit the amount conveyed by the fan to the cooling air throughput required for engine cooling. Yet, a sufficiently large quantity of cooling air is available for the engine compartment. Although in this case the engine compartment is ventilated with "warm" waste air of the ring radiator, thanks to the larger air throughput as compared to known systems a more uniform ventilation throughout and an improved cooling of the engine compartment are attained.
Especially advantageous relationships with respect to the width of the air-conducting housing and the air throughput in the engine compartment result by associating, according to this invention, approximately one-third to one-half of the ring radiator periphery with the waste air chamber in communication with the engine compartment.
In this arrangement, a ratio of the width of the air outlet to the diameter of the ring radiator is obtained which is about 1.1, whereas in the other case, i.e., when the entire amount of waste air of the ring radiator must flow off toward one side, the ratio is about 1.4.
In accordance with this invention, the air outlet for the engine compartment waste air is disposed below the air outlet for the radiator air, to attain an intensive flow of the air through the entire engine compartment.
The advantages attained by means of the present invention reside particularly in that a small structural width of the air-conducting housing is obtained, because the partial amount of the ring radiator waste air passing into the engine compartment need not be conducted in the air-conducting housing around the ring radiator to the air outlet; that this improved conductance of the waste air ensues in a uniform load on all ring radiator peripheral zones; and that thereby, with the same power input into the fan, a higher cooling efficiency results for the recooling of the coolant of the internal combustion engine.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.